The U.S. Department of Energy on December 12 announced a breakthrough in ongoing research for nuclear fusion, long heralded for its potential as a source of essentially limitless zero-emissions energy.
Key points
- In an experiment on 5 December 2022, the Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) fusion reactor, based in California, generated a power output of 3.15 megajoules from a laser power output of 2.05 megajoules – a gain of around 150 per cent.
- However, this is far outweighed by the roughly 300 megajoules drawn from the electrical grid to power the lasers in the first place.
- This is first time on Earth, a controlled fusion reaction has generated more power than it requires to run.
- The experiment is a major step towards commercial fusion power, however, experts say there is still a more efforts needed to increase efficiency and reduce cost.
Approaches to nuclear fusion
- There are two main research approaches aiming to achieve viable nuclear fusion. The first uses magnetic fields to contain a plasma, the second approach uses lasers.
- The National Ignition Facility (NIF) fusion reactor uses the second approach, known as inertial confinement fusion (ICF), where a tiny capsule containing hydrogen fuel is blasted with lasers, causing it to heat up and rapidly expand.
- The ICF process creates an equal and opposite reaction inwards, compressing the fuel. The nuclei of hydrogen atoms then fuse together to form heavier elements and some of their mass is released as energy – just as it is in the sun.
Previous experiments
- Before NIF experiment, all fusion experiments have required more energy input than they generate.
- Most fusion investment is currently poured into the alternative approach of magnetic confinement, in particular a reactor design called a tokamak.
- Joint European Torus (JET) reactor near Oxford, UK: It began operating in 1983. When running, it is the hottest point in the solar system, reaching 150 million°C (270 million°F). Earlier this year, JET sustained a reaction for 5 seconds, producing a record 59 megajoules of heat energy.
- International Thermonuclear Experimental Reactor (ITER) in France: This is nearing completion and its first experiments are due to start in 2025.
- Korea Superconducting Tokamak Advanced Research (KSTAR): It recently managed to sustain a reaction for 30 seconds at temperatures in excess of 100 million°C.
About Nuclear Fusion
- Nuclear fusion is the process of fusing two or more atoms into one larger one, a process that unleashes potentially usable energy as heat, in much the same way as the sun heats the Earth.
- The nuclear power used today is created by a different process, called fission, which harnesses the energy produced by splitting atoms but also produces radioactive waste that must be safely contained.
